In general, a door provides a function of forming an independent space by dividing the space from another space using steel or wood.
A steel door is disposed at an outdoor space and has functions as a gate and crime prevention, like a front door, and a wooden door is disposed between a space and another space so as to divide an indoor space.
Here, the wooden door has a function of selectively shielding a space formed by a doorframe, including a doorpost and a door threshold combined with each other, between walls of an indoor space and, for example, a sliding door, a hinged door, etc. are representatively used as wooden doors.
Among these wooden doors, in case of a hinged door mainly used indoors, at the moment when the hinged door is opened and closed, safety accidents are frequently generated between the door and a doorpost.
Therefore, in order to protect infants or children from safety accidents, an elastic material, such as a sponge, is inserted into the front end of a door, or a door holder to prevent closing of a door is mounted on the door.
However, such an elastic material is inserted into the front end of the door, only as needed, and then is released from the door, thus causing cumbersomeness. Further, if an infant bites or touches the elastic material, the elastic material may be released from the door. Moreover, the door holder causes a door to be open at all times.
If the elastic material is released from the door or an infant manipulates the door holder mounted at the lower part of the door, the infant may get hurt physically or mentally.